Are Airplane Wings Getting a New Design?

How Shape-Memory Alloys Allow Wings to Fold Up and Down Efficiently

January 26, 2018,
Bruno Jacobsen

It would be a stretch to say that airplane wings haven't changed much over the years. But to the less careful observer, at least aesthetically, that's what it seems like. But that could be all about to change, as NASA just tested airplane wings that fold up and down - much like bird wings.

Are Airplane Wings Getting a New Design?

On January 19, 2018, NASA announced it had tested a new alloy to fold wings in flight.

These new alloys are called shape-memory alloys, or SMAs for short. In essence, the material responds to heat by changing and restoring its original form, in this case by folding upwards or downwards.

In the test aircraft one could see tubes perpendicular to the wingspan with thermal memory. Upon being heated, the wings then fold upwards or downwards by up to 70-degree angles.

The alloy is lightweight and displays superelasticity, which could significantly reduce the weight and efficiency of aircraft systems going forward.

Conducted as part of the Spanwise Adaptive Wing (SAW) project, this new technology creates new possibilities which would have otherwise required heavy and inefficient hydraulics.

Benefits for airplanes

According to NASA, this could confer airplanes several benefits.

For one, it is expected to increase performance as we transition from subsonic to supersonic speeds. By folding the wings downwards, airplanes can reduce drag and "ride the wave." The reduced drag also increases the efficiency of the planes.

But even for current subsonic flights the benefits aren't small.

Folding the wings allows for increased controllability of the aircrafts and reduces dependency on the heavier parts of the plane. This can mean increased fuel-efficiency. On top of that, pilots would be able to control the wings to adapt to any sort of flight conditions. But it can also play an important role in airports. With folded wings, airplanes free up space in airports and longer-winged aircrafts become possible.

Going forward

According to Matt Moholt, SAW's Principal Investigator, they will now use this data to continue improving on the system.

As they continue working through 2018, we can expect the system to fold the wings more smoothly and quickly.

The wings can also only be folded in one direction at the moment. Going forward, they'll be trying to make it move in both directions during a single flight.

But with the long planning and lead times in airplane manufacturing, we may have to wait a while to see any of this applied to commercial airlines.